Preparation
Whisk first 9 ingredients in medium bowl to blend.
Add enough water to a large saucepan to reach depth of ½ inch. Bring water to a boil. Add sweet potatoes and cook until just tender, about 5 minutes. Drain and cool potatoes. Mix sweet potatoes, dressing, peas, and green onions in large bowl. Season salad with salt and pepper. (Can be made 4 hours ahead. Cover and refrigerate.)
Sprinkle salad with peanuts and serve.